The present invention relates to a bending machine for pipes, sections and similar, enabling any number of bends to be formed fully automatically, even zigzag bends with very tight bend radii, as required for special applications such as furniture. The machine covered by the present invention is specially designed for accommodating a numerical control unit for controlling the machine according to a given operating routine.
Utility model application No. 53552-B/80, filed on Oct. 3, 1980, relates to a fully-automatic zigzag bending machine essentially comprising two pairs of parallel feed rollers, between which the pipe is fed in a given first direction, and a third pair of bend rollers parallel with the former. The latter rollers are mounted in idle manner on a table turning round an axis lying in the same plane as and at the same distance from the axes of the said third pair of rollers. The said turntable is fitted on a slide travelling in a direction essentially perpendicular to the pipe feed direction.
On the said machine, the pipe is first fed by the said feed rollers through the said third pair of bend rollers, after which, the said slide is shifted in such a manner as to cause one of the said bend rollers to exert sufficient bending force on the pipe, essentially perpendicular to the feed direction. During the latter operation, the table on which the bend rollers are mounted turns round its rotation axis into a position whereby the said plane containing the axes of the two bend rollers is essentially perpendicular to the tangent of the bend pipe axis.
Though the aforementioned machine provides for fully-automatic zigzag bending and the production of fine quality semifinished parts, it does not enable the formation of bends having very tight bend radii. Such are prevented by the position assumed by both the turntable, on which the bend rollers are mounted, and the slide, which causes one of the said two bend rollers to contact one of the said feed rollers. Consequently, the minimum bend radius obtainable on the aforementioned machine is that allowed by the said turntable-slide arrangement.